Safe to skip radiation for prostate cancer?

NEW YORK (Reuters Health) - A review of recent studies comparing different radiation treatments for prostate cancer reveals no clear picture of what works best for the majority of men with the disease.

Unlike many other cancers, prostate cancer often grows slowly and may never progress to the point where it threatens a man's life. This complicates treatment decisions, because therapies for prostate cancer carry risks -- including long-term urinary incontinence and erectile dysfunction. So for many men, treating the disease could potentially do more harm than good.

As a result, experts are increasingly calling for expanded use of active surveillance, sometimes called watchful waiting, in managing prostate cancer. This can mean regular blood tests, visits to a urologist, and repeat biopsies, for example.

However, no large studies have done a sufficient job of comparing what happens to men who opt for active surveillance and those who receive radiation right away, making it difficult for doctors to give sound advice about the safety of holding off on radiation therapy, study author Dr. Raveendhara Bannuru at Tufts Medical Center told Reuters Health. "We had insufficient evidence to give any specific recommendations on that."

The lack of a conclusion was not a surprise to Dr. Peter Albertsen of the University of Connecticut Health Center in Farmington, who reviewed the findings for Reuters Health. In previous studies, prostate cancer patients who chose to forgo radiation were often "fundamentally different" from those who chose treatment - they were generally healthier or their cancer was less aggressive, for instance - which makes comparisons between the two difficult, he said.

As a result, for the majority of men who are faced with the choice, the main option is to speak with their doctors, radiation therapists, and surgeons, then "go back and try to decide what's right for you," Albertsen told Reuters Health.

"Decisions regarding treatment choice for localized prostate cancer should always be a shared decision between the patient and his physician," agreed Dr. Timothy Daskivich of the University of California, Los Angeles, who also reviewed the findings for Reuters Health.

Prostate cancer is the most common cancer among U.S. men. One in six will eventually develop it.

The advent of prostate cancer screening with blood tests for PSA (prostate-specific antigen) has meant that a large number of men are now diagnosed with early stage cancer that's unlikely to ever become life-threatening. Indeed, most men are diagnosed with a localized form of the disease, meaning it has not spread throughout the body.

Recently, researchers have been finding that it may be okay for some men to skip treatment. Last year, researchers found that among 466 patients who chose active surveillance rather than immediate treatment, those with tumors at intermediate risk for progression fared as well as men with low-risk prostate cancer over four years. Earlier this year, Albertsen and his colleagues found that option may be safe even for some older men with riskier forms of the disease.

In the current study, published in the Annals of Internal Medicine, Bannuru and his colleagues reviewed 75 studies that looked at the benefits of different types of radiation therapy in prostate cancer, and the risks of skipping it altogether.

Unfortunately, the studies didn't all evaluate the same results. Also, most allowed patients to select which treatment they received. That makes the comparisons unreliable, because the results could be influenced by differences between people who selected different types of treatment, said study author Dr. Mei Chung, who works with Bannuru at Tufts.

However, the authors found enough convincing evidence to suggest that higher doses of radiation beamed at the prostate - usually an extra 1500 rads, said Albertsen -- are more effective at bringing down PSA to a healthy level, with no extra urinary or bowel side effects.

Extra treatment often brings extra risks, cautioned Bannuru, and the studies tracked men for no more than a few years, so it's not clear whether the additional radiation might cause more problems in the longer term.

Fortunately, researchers in the UK and Canada are comparing outcomes in similar men who were randomly selected to receive either no treatment or surgery and radiation, and these studies will hopefully help determine which men can safely skip treatment, said Bannuru. "We expect results from these trials will help clarify some concerns."

This type of study has been difficult to conduct in men with prostate cancer, Daskivich told Reuters Health in an email. "Patients generally don't want to be enrolled in a study where they're randomized to either surgery or radiation; they want to make the decision for themselves," he said. "And they certainly don't want to be randomized to a trial of therapy vs. no therapy."

According to the American Cancer Society, approximately 27,000 men died of prostate cancer in 2009.